The liner in the combustor of a gas turbine engine is subject to a severe thermal environment. The maximum combustion temperature to which the liner can be subjected before it experiences a structural failure, such as by buckling or cracking, imposes an operational limitation upon the engine. Additionally, damage to a portion of a conventional continuous liner requires replacement of the entire liner.
An improved combustor liner arrangement has been developed to reduce structural failures and to facilitate replacement of only a damaged portion of a liner rather than the entire liner. The new arrangement comprises a plurality of liner panels disposed axially and circumferentially adjacently to each other and slidably mounted on a structural frame. Such a liner arrangement is disclosed in U.S. Pat. No. 4,253,301--Vogt, filed Oct. 13, 1978, and assigned to the same assignee as the present invention.
The panels of a liner can be fabricated by numerous methods. However, due to the complex shape of each panel, a suitable, commonly used method of fabrication comprises casting the panels.
Although casting the panels is an acceptable method of fabrication, it results in certain limitations. For example, under current casing technology, the thinnest portions of the cast panel have a minimum thickness, generally larger than required for adequate structural strength. The minimum castable thickness adds unnecessary weight to the panel and increases the weight of the combustor and the engine. Furthermore, the additional cast material required to obtain the minimum thickness adds to the cost of the panel.
Another limitation of casting the liner panels is cost. The casing machinery employed and time required to subsequently machine the panels can be relatively expensive, thus increasing the overall cost of an engine.
It is therefore an object of the present invention to provide a new and improved method of fabricating sheet metal panels.
Another object of the present invention is to provide a new and improved method of fabricating panels in which the amount of material required for the panel is less than that required using a casting method and thus the weight of the panels is reduced.
Another object of the present invention is to provide a new and improved method of fabricating panels in which the fabrication time and complexity are reduced.
Another object of the present invention is to provide a new and improved fabricated panel article.